On Fri, Jul 09, 2004 at 04:16:32PM -0400, Daniel Phillips wrote: > Let's work though this nice and slowly please. You're saying that LVM2 > can go change the table, e.g., by inserting a mirror for pvmove, at any > time. Yes. Applications like LVM2 should be free to insert new layers & split targets up whenever they want. > But if that happens, we can end sending the message to the wrong > target (e.g., a temporary mirror instead of the snapshot target) This is one of the complexities still to be worked out: how we see that the message (ie the ioctl "payload") gets passed on down to the right layer. If it's done by index and there are multiple layers - no chance. If it's done by sector, I think it's possible. And it probably requires that the "payload" strings conform to a standard too, so that the right target knows to intercept them. [There are alternative approaches; intend to explore each of them before making decisions.] Alasdair -- agk@xxxxxxxxxx